Method of making sound brass castings



UNITED STATES PATENT OFFICE.

LEONlVIoCULLOCI-I, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR 'IO WESTINGHOUSE .ELEGTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

METHOD OF MAKING SOUND BRASS CASTINGS.

No Drawing.

To on whom it may concern:

Be it known that I, LEON MoGULLocn, a itizen of the United States, and a resident of ilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Making Sound Brass Castings, of which the 'l'ollowing is a specification.

My invention relates to methods of maklug metal castings and more particularly castings of copper or of copper alloys, such as brass and bronzes, and it has for its pri mary object the obviation, to a substantial extent, of blow-holes or porous structures in castings of this character.

In the course of an investigation into the cause of blow-holes in copper-containing castings. I have found that hydrogen gas is absorbed by the metal when it is melted and given up again upon cooling, resulting in serious blow-holes or, in cases where the gas is not able to escape. porous castings.

For this reason. one object of my invention resides in the provision of a. method of freeing melted copper or its alloys of all absorbed hydrogen before it is employed for casting purposes.

1 have found that it is'possible to'free melted metals of such character from hydrogen by oxidizing them with air or by the addition of suitable oxidizing agents. For example, I may stir into the melted metal any suitable metallic oxid or oxids, such as zinc oxid, copper oxid or both.

Experience has shown that the addition, to the melted copper or its alloy, of a small amount of copper containing dissolved suboxid of copper is very effective in removing the hydrogen, as the oxid is rapidly disseminated through the melted metal and so hastens the removal of the absorbed hydrogen, the oxygen of the oxid combining with hydrogen and escaping as water vapor. Any surplus oxids come to the surface of the metal where they may be skimmed off.

The amount of sub-oxid required and the amount of copper in which it may suitably be dissolved will vary, in different cases, and may best be determined, in each instance, by preliminary tests.

In copper casting, good results are obtained by adding an excess of copper containing copper oxid and then removing the oxygen by a suitable deoxidizer, such as silicon, phosphor-copper or the like. With brass, any excess of oxygen is automatically Specification of Letters Patent.

Application filed January 16, 1919.

Patented Aug. 31, 1920.

Serial No. 271,537.

removed by reaction with the zinc. However, other impurities may be present which will be removed by a deoxidizer, so its use is not injurious even if it is not required for re. moving excess oxygen.

\Vhile it is true that other gases, such as chlorin, coming from salt which may be used as aiiux in brass casting, or water vapor from the sand employed during casting, or carbon monoxid gas from the fuel utilized, as well as entrapped air, may cause blowholes in such castings, or porosity of the castings. 'it is nevertheless true that hydrogen is the most usual cause of such dithculties and that ,.its elimination from the copper or copper alloys prior to casting, will materially decrease, if not entirely obviate, these ditliculties.

As various methods of supplying a suitable oxidizing agent may be resorted to and as different oxidizing agents may be employed under different circumstances, no limitations are to be imposed upon my invention other than those indicated in the claims.

I claim as my invention:

1. The method of making sound castings of copper or copper alloys which comprises oxidizing and consequently removing absorbed hydrogen from the molten metal prior to casting.

2-. The method of making sound castings of'copp'er or copper alloys which comprises adding an oxidizing agent to the metalin molten condition, whereby the oxygen may combine with the absorbed hydrogen of the metal to escape as water vapor.

3. The method of forming sound castings of copper or copper alloys which comprises adding a metallic oxid to the metal in a molten state.

4. The method of forming sound castings of copper or copper alloys which comprises adding copper contalning dissolved suboxid of copper to the metal while the latter is in a molten c0ndition.-

5. The method of forming sound castings I of copper or copper alloys which comprises adding copper containing dissolved suboxid of copper to the metal while the latter is in a molten condition and adding a deoxidizer to remove excess oxygen.

In testimony whereof, I have hereunto subscribed my name this 31st day of Dec.,

LEON MoOULLOCH. 

